There are already known systems in which a measurement zone is set up on a rail, e.g., from the document DE 10 2006 015 924 A1. With these known systems, a plurality of measurement devices is arranged beneath the rail in the longitudinal direction of the rail to detect the forces acting on the rail. By means of these measurement devices, the forces or torques occurring when the rail vehicle travels over the rail can be measured in the body of the track. However, such known systems are limited to measuring the forces or torques occurring in the rail, which allows only a limited diagnosis with respect to the condition of the running gear of the rail vehicle. With these systems, for example, it is thus possible to detect flat spots on wheels of rail vehicles, but this can only be done with a quality statement which is derived merely from the force measurement technique. Therefore, statements about the geometric properties of the flat spots are possible only to a limited extent.
Furthermore, there are also known systems for detecting overheated axle bearings of rail vehicles, also known as hot box detectors, in the state of the art. However, such systems have the disadvantage that they are able to detect bearing damage to the wheel or axle bearing on the rail vehicle only when the condition of the vehicle of the rail vehicle is already relatively critical.
The known hot box detectors are usually based on the principle of infrared measurement technology and can thus supply information about possible bearing damage only by way of a temperature difference measurement. For maintenance on rail vehicles as well as rail operators the hit ratio and the reliability of accurate information of diagnostic systems about the condition of the running gear of rail vehicles are of crucial importance.